The present invention generally relates to venting, exhaustion and/or admission of air in piping systems. More specifically, the present invention relates to a damper system and a method for controlling the entrance and exhaust of air into and from a venting system of a pipeline or reservoir.
Venting systems are used with pipelines to prevent vacuum conditions within a liquid pipeline, and to allow for exhaust or purging of gases from the liquid carried in the pipeline. In the case of an underground pipeline, such as used with potable water systems or waste or ground water systems, oftentimes the vent connections occur in underground vaults and reservoirs, which themselves need to be vented to the atmosphere. Although the pipes may be buried well below the frost line, if sub-freezing air flows into the vault due to the vault being vented, it is possible for the liquid in the pipeline to freeze, thereby damaging the pipeline. Also, various valves utilized in the vent system and located in the vault may be subject to damage or operational deficiencies if frost or ice builds up on the valve components.
Various types of dampers are known for use with vent pipes, including baffles that are moved by means of a motor, or baffles that are pivotally mounted and that move to a normally closed position by gravity due to a weighted baffle. The motorized baffles require electricity to operate and may not have an open fail safe condition in the event of a power loss. The motorized baffles also typically are pivotally mounted and if a build up of frost or ice occurs on the baffle, they may be prevented from pivoting into an open position, even under the power of the motor. The weighted baffles must be mounted in a horizontal pipe run in order for the baffle to be oriented correctly in the vent pipe to close the pipe when no gas is flowing through the vent pipe. These weighted baffles also are typically pivotally mounted and thus suffer the same problems described above due to ice and frost build up.
A need exists for an improved damper for a vent pipe that will allow for gas flow in either direction upon a certain threshold pressure differential across the baffle, yet will normally prevent the flow of gas below the determined threshold pressure differential, which will address the problems previously described.